JP4909027B2 - Engine driven compressor - Google Patents

Description

  The present invention relates to an engine-driven compressor, and more particularly to an engine-driven compressor capable of appropriately setting a discharge pressure.

  As an apparatus for supplying compressed air having an arbitrary discharge pressure, for example, an engine-driven compressor driven by an engine is known. The engine-driven compressor is a device that compresses the intake air and pressurizes and supplies it to the required discharge pressure. The discharge pressure supplied by the engine-driven compressor is the pressure adjustment valve provided in the engine-driven compressor. Determined by the set pressure value.

  However, engine-driven compressors require different discharge pressures depending on work contents. For example, a low pressure of about 0.69 MPa may be used for normal painting / concrete spraying work and air blowing work, but a high pressure of 0.78 MPa to 2.40 MPa is required for down-the-hole construction, large-diameter boring work, and the like.

  In the down-the-hole method, a high pressure is required when excavating the rock layer and the boulder layer, but a low pressure may be used in other cases.

  In this way, in order to supply different discharge pressures depending on the work content, either an engine-driven compressor equipped with a pressure adjustment valve corresponding to the supplied discharge pressure is prepared, or the set pressure value of the pressure adjustment valve is set according to the work content. It was necessary to re-adjust, which was a problem from the viewpoint of cost and work efficiency.

Therefore, in order to supply different discharge pressures as described above, conventionally, an engine-driven compressor has two pressure regulating valves having different set pressure values connected in parallel, and one pressure regulating valve can be freely opened and closed. A technique is disclosed in which a valve is provided and the discharge pressure supplied by opening and closing the valve is switched (see, for example, Patent Document 1).
JP 2001-116209 A (paragraphs 0010 to 0011, FIG. 1)

  However, in the engine-driven compressor disclosed in Patent Document 1, piping is necessary for each of the two pressure regulating valves, so that the piping is complicated, the manufacturing cost increases, and the engine-driven compressor main body becomes large. There's a problem.

  The discharge pressure required for the engine-driven compressor is generally 0.69 MPa, 0.78 MPa, 0.83 MPa, 1.03 MPa, 1.27 MPa, 2.07 MPa, 2.40 MPa, etc. The engine-driven compressor disclosed in Patent Document 1 has a problem that only two types of discharge pressures can be selected.

  Therefore, an object of the present invention is to supply an engine-driven compressor that can set an arbitrary discharge pressure and can supply compressed air of the set discharge pressure.

In order to solve the above-mentioned problem, the invention according to claim 1 includes a rotational speed detecting means having a function of detecting a rotational speed and a function of converting the detected rotational speed into a predetermined electric signal and outputting the same. An engine, a compressor main body driven by the engine, a storage means for storing compressed air compressed by the compressor main body, and a first pressure detection for detecting a pressure of the compressed air stored in the storage means The engine drive compressor is configured to include a means, a pressure setting means capable of setting an arbitrary discharge pressure, and an intake air adjustment valve that adjusts an intake air amount of intake air taken into the compressor body. Then, as mentioned above the pressure in the reservoir means is equal to the set pressure, by controlling the intake control valve, comprising a control means for adjusting the intake air amount of the intake air to the compressor body, said control means Is a first electric signal input means for inputting the electric signal output from the rotation speed detecting means, and engine rotation speed setting data used for setting the engine rotation speed corresponding to the discharge pressure. And a rotation speed of the engine calculated based on the electric signal input to the first electric signal input means is set to the set discharge pressure and the engine rotation speed setting data. An engine rotation speed control unit that gives a command to the engine so as to be equal to a rotation speed set based on the rotation speed .

According to the first aspect of the present invention, the pressure of the compressed air stored in the storage unit can be arbitrarily set by the pressure setting unit. And the pressure of the compressed air stored in the storage means and the set pressure can be maintained equally.
Further, the control means can calculate the engine rotation speed, and controls the engine so that the engine rotation speed is based on the set discharge pressure and the engine rotation speed setting data stored in the storage unit. be able to.

  According to a second aspect of the present invention, the opening of the intake control valve is controlled by the pressure of control air input for adjusting the opening, and the pressure of the control air is output to output the intake control valve. The engine-driven compressor further includes a valve control means for controlling the opening degree of the engine and a second pressure detection means for detecting the pressure of the control air. Then, the opening of the intake control valve is controlled by adjusting the pressure detected by the second pressure detecting means via the valve control means, so that the pressure in the storage means becomes equal to the discharge pressure. Thus, it has a control means for adjusting the intake amount of the intake air to the compressor body.

  According to the second aspect of the invention, the pressure of the compressed air stored in the storage means is set by adjusting the amount of intake air to the compressor body by adjusting the pressure of the air that controls the intake control valve. Can be maintained at an equivalent pressure.

According to a third aspect of the present invention, the first pressure detection means and the second pressure detection means have a function of converting the detected pressure into a predetermined electric signal and outputting the predetermined electric signal. a third electrical signal input means for inputting a second electrical signal input means for inputting said electrical signal is the first pressure detecting means for outputting, the electrical signal by the second pressure detecting means outputs said second Based on the electrical signal input to the electrical signal input means, the pressure detected by the first pressure detection means is calculated, and based on the electrical signal input to the third electrical signal input means, And an arithmetic unit for calculating a pressure detected by the second pressure detecting means.

  According to the invention of claim 3, the control means can detect the pressure detected by the first pressure detection means and the second pressure detection means as an electrical signal.

  According to a fourth aspect of the present invention, the pressure setting means operates a display unit that displays the discharge pressure value as a plurality of numerical values and a direction that increases the numerical value displayed on the display unit one by one. And an operation unit having a down button that can be operated in a direction to lower the numerical value by one.

  According to the fourth aspect of the present invention, the pressure setting means can display the set discharge pressure value as a plurality of numerical values, and can increase or decrease the numerical value one by one with the up button and the down button.

The invention according to claim 5 is characterized in that the valve control means is constituted by an electropneumatic proportional valve.

According to the fifth aspect of the present invention, an electropneumatic proportional valve can be used as the valve control means.

  According to the present invention, there is provided an engine-driven compressor that can arbitrarily set a discharge pressure from three or more different discharge pressures and can supply the set discharge pressure with only one engine-driven compressor. can do.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings as appropriate.

  FIG. 1 is a block diagram showing a schematic configuration of an engine-driven compressor according to the present embodiment. The engine-driven compressor 1 is an oil that separates the compressor main body 2, the engine 3 that drives the compressor main body 2, and the oil that is mixed with the compressed air compressed by the compressor main body 2, and stores the compressed air. And a chamber (storage means) 4.

  The compressor body 2 is provided with an intake pipe 2b whose one end is open to the atmosphere side. When the engine-driven compressor 1 is operated, air outside the compressor body 2 is sucked through the intake pipe 2b. It can be taken into the compressor body 2 (hereinafter referred to as intake air). An air cleaner 2c may be provided on the side of the intake pipe 2b that opens to the atmosphere. By providing the air cleaner 2c and sucking the intake air into the compressor body 2 through the air cleaner 2c, foreign matter in the intake air can be removed.

  And the compressor main body 2 and the oil chamber 4 are connected by the discharge pipe 4b, and the compressed air compressed by the compressor main body 2 is sent to the oil chamber 4 via the discharge pipe 4b. The oil chamber 4 is provided with a service valve 4a, and compressed air stored in the oil chamber 4 is supplied to the load by operating the service valve 4a.

  In the present embodiment, the compressor main body is configured so that the function of setting the pressure of the compressed air stored in the oil chamber 4 (hereinafter referred to as storage pressure) is equal to the set pressure. 2 is provided with a control unit (control means) 5 for controlling the intake air amount of the intake air to the air inlet 2.

  The control unit 5 compares the pressure set as the storage pressure (hereinafter referred to as the set pressure) with the storage pressure by the pressure setting means, and if the storage pressure and the set pressure are not equal, the storage pressure is set. The intake air amount of the intake air to the compressor body 2 is adjusted so that the pressure becomes equal, and further, the engine rotation speed of the engine 3 is increased or decreased.

  As described above, in order to adjust the intake air amount of the intake air to the compressor main body 2 by the control unit 5, the compressor main body 2 is provided with a capacity regulator (intake control valve) 2a. It is controlled by the pressure of air (hereinafter referred to as control air in the present invention) output from the air proportional valve (valve control means) 5a.

  The electropneumatic proportional valve 5a has, for example, an electrical on-off valve in an air flow path through which compressed air input from a compressed air source flows, and corresponds to an input control signal (for example, a current value or a voltage value). In this device, the opening of the on-off valve is adjusted, the air pressure of the compressed air of the compressed air source input upstream of the on-off valve is adjusted, and an arbitrary air pressure is output downstream of the on-off valve. And in this embodiment, the electropneumatic proportional valve 5a is connected to the capacity | capacitance regulator 2a with which the compressor main body 2 is provided via the non-return valve 5b and the orifice 5c. In addition, the electropneumatic proportional valve 5a is not specifically limited, What is necessary is just to use a general purpose thing.

  The capacity regulator 2a adjusts the flow rate of the air flowing through the intake pipe 2b by adjusting the intake pipe 2b in the range from opening to closing, for example, corresponding to the pressure of the control air output from the electropneumatic proportional valve 5a. Thus, the device adjusts the amount of intake air taken into the compressor body 2.

  FIG. 2 is a sectional view of the capacity regulator. As shown in FIG. 2, the capacity regulator 2a has an air inlet 2a1 and an air flow path 2a2, and the air inlet 2a1 opens on the side surface of the air flow path 2a2 toward the outside of the capacity regulator 2a. . An intake pipe 2b is connected to the intake port 2a1, and intake air sucked through the intake pipe 2b passes from the intake port 2a1 to the compressor body 2 (see FIG. 1) via the air flow path 2a2. Inhaled.

  The air flow path 2a2 is provided with an open / close valve 2a4 that can move in the direction of approaching or leaving the intake port 2a1, and the opening degree of the intake port 2a1 can be adjusted. Normally, the biased force of the opening / closing spring 2a5 is held in a state of moving away from the intake port 2a1, and the intake port 2a1 is opened. Thus, by adjusting the opening degree of the intake port 2a1, the intake pipe 2b can be adjusted in a range from opening to closing. The side of the on-off valve 2a4 opposite to the intake port 2a1 is housed in an L chamber 2a3 having a nozzle 2a6, and control air is input to the L chamber 2a3 from the electropneumatic proportional valve 5a. When control air is input from the electropneumatic proportional valve 5a to the L chamber 2a3, the control air flows into the compressor body 2 (see FIG. 1) as leaked air through the nozzle 2a6. However, when the amount of air input from the electropneumatic proportional valve 5a to the L chamber 2a3 increases and the pressure applied to the open / close valve 2a4 exceeds the biasing force of the open / close spring 2a5, the open / close valve 2a4 When the opening 2a1 is moved in a direction close to the intake port 2a1 by the pressure of the pressure and the opening degree of the intake port 2a1 is reduced and the on-off valve 2a4 is pressed around the intake port 2a1, the intake port 2a1 is closed. In FIG. 2, a two-dot chain line (imaginary line) indicates a state where the intake port 2a1 is closed. The capacity regulator 2a is not particularly limited, and a general-purpose one may be used.

  Here, in this embodiment, as shown in FIG. 1, compressed air stored in the oil chamber 4 as a compressed air source is input to the electropneumatic proportional valve 5a. However, since the storage pressure of the oil chamber 4 varies with, for example, fluctuations in the amount of air supplied to the outside via the service valve 4a, the pressure of the control air output from the electropneumatic proportional valve 5a In some cases, the capacity regulator 2a may not be properly controlled due to fluctuations in the storage pressure of the oil chamber 4 that is input. For this reason, it is preferable to correct the control amount of the electropneumatic proportional valve 5a calculated by the calculation unit 50 by detecting the pressure of the control air and inputting it to the calculation unit 50 (see FIG. 3) of the control unit 5.

  For this reason, a second pressure sensor (second pressure detection means) 5d for detecting the pressure of the control air is provided downstream of the electropneumatic proportional valve 5a. The second pressure sensor 5d is not particularly limited. For example, a sensor that outputs a change in air pressure as an electrical signal (voltage or the like) using a general-purpose pressure-sensitive element may be used. Further, if the control unit 5 and the second pressure sensor 5d are connected by a signal line, an electric signal output from the second pressure sensor 5d is input to the control unit 5 as a pressure signal of control air. Good. The control unit 5 can calculate the pressure detected by the second pressure sensor 5d based on the input electrical signal.

  As shown in FIG. 1, the engine 3 includes an engine control unit (Engine Control Unit: hereinafter referred to as ECU) 3 a that controls the rotation speed and the like. The control unit 5 is connected to the ECU 3a through a signal line, and the control unit 5 controls the ECU 3a with an engine rotation speed control signal to control the engine rotation speed and the like of the engine 3.

  The control unit 5 feeds back the engine rotation speed of the engine 3 so that the engine 3 is provided with a rotation speed detecting means 3b. The rotational speed detecting means 3b is not particularly limited, and for example, a general-purpose electromagnetic pickup type sensor may be used. The electromagnetic pickup type sensor can output the engine speed as the frequency of the AC voltage, and the frequency of this AC voltage is proportional to the engine speed. Therefore, the AC voltage (electric signal) is used as the engine speed signal, and the signal line is It may be configured to input to the control unit 5 via With this configuration, the control unit 5 can calculate the engine speed of the engine 3 from the frequency of the input AC voltage.

  Further, the control unit 5 is configured to detect the storage pressure in order to compare the set pressure and the storage pressure. Therefore, the oil chamber 4 is provided with a first pressure sensor (first pressure detection means) 4c. The 1st pressure sensor 4c is not specifically limited, For example, what is necessary is just to use the thing equivalent to the 2nd pressure sensor 5d. The first pressure sensor 4c is not limited to being provided in the oil chamber 4, and may be provided in a pipe between the oil chamber 4 and the service valve 4a. The first pressure sensor 4 c may be configured to convert the detected pressure into a predetermined electrical signal and input it to the control unit 5. The control unit 5 calculates the pressure detected by the first pressure sensor 4c based on the input electrical signal.

FIG. 3 is a block diagram showing the configuration of the control unit. The control unit 5 executes various arithmetic processes and operates a calculation unit 50 including a CPU (Central Processing Unit) (not shown) and peripheral circuits for driving the control unit 5, programs for operating the calculation unit 50, and various data And the like, a discharge pressure setting section (pressure setting means) 52 for setting the discharge pressure by inputting the pressure value, and a first pressure signal for inputting an electric signal output from the first pressure sensor 4c. Input part ( second electric signal input means) 53a and second pressure signal input part ( third electric signal input means) 53b for inputting an electric signal output from the second pressure sensor 5d and engine 3 (see FIG. 1) having an engine rotational speed input unit for inputting an engine rotation speed signal an engine rotational speed detection means 3b for detecting the engine rotational speed is outputted (the first electrical signal input means) 53c An engine speed control signal output unit 54a for giving a command to the ECU 3a of the engine 3 by outputting a signal input unit 53, an engine speed control signal, and an electropneumatic proportional valve control signal output unit for outputting an electropneumatic proportional valve control signal A control signal output unit 54 having an engine speed 54b, and an engine rotation speed control unit 55 for controlling the engine rotation speed.

  The engine rotation speed control unit 55 inputs an engine rotation speed signal via the engine rotation speed input unit 53c, and calculates the engine rotation speed of the engine 3 (see FIG. 1) from the input engine rotation speed signal. The engine rotation speed control unit 55 is connected to the calculation unit 50 through a signal line, and an engine rotation speed (hereinafter referred to as a requested rotation speed) corresponding to the set pressure calculated by the calculation unit 50 is input.

  When a deviation occurs between the engine rotation speed of the engine 3 (see FIG. 1) calculated by the engine rotation speed control unit 55 and the requested rotation speed input from the calculation unit 50, the engine rotation speed control signal output unit 54a is set. Then, an engine rotation speed control signal is output to the ECU 3a, and the engine rotation speed is controlled so that the engine rotation speed of the engine 3 (see FIG. 1) is equal to the required rotation speed. The engine speed control signal is not particularly limited, and may be an electric signal based on a voltage value, a current value, or the like, or may be a digital signal such as a serial command, or a signal corresponding to the specification of the ECU 3a may be used. .

  When the storage pressure becomes lower than the set pressure due to an increase in the amount of air supplied to the outside via the service valve 4a (see FIG. 1), the storage unit raises the storage pressure. Outputs an electro-pneumatic proportional valve control signal to the electro-pneumatic proportional valve 5a via the electro-pneumatic proportional valve control signal output unit 54b to adjust the pressure of the control air so that the opening of the intake pipe 2b is greatly opened. The capacity regulator 2a is controlled. The electro-pneumatic proportional valve control signal is not particularly limited, and may be a signal corresponding to the specification of the electro-pneumatic proportional valve 5a to be used, such as an electric signal based on the magnitude of the current value.

  Further, the calculation unit 50 of the control unit 5 calculates a required rotation speed of the engine 3 (see FIG. 1) based on the set pressure and notifies the engine rotation speed control unit 55 of the calculation. Then, an engine rotation speed control signal is output to the ECU 3a (see FIG. 1) via the engine rotation speed control signal output unit 54a, and the engine rotation speed is increased so as to increase the engine rotation speed of the engine 3 (see FIG. 1). Control the speed. In this way, the amount of air discharged from the compressor body 2 is increased by increasing the engine speed.

  In addition, when the service valve 4a is closed or the amount of air supplied to the outside via the service valve 4a decreases, the storage pressure rises and exceeds the set pressure, the calculation unit 50 of the control unit 5 Outputs an electro-pneumatic proportional valve control signal to the electro-pneumatic proportional valve 5a via the electro-pneumatic proportional valve control signal output unit 54b to adjust the pressure of the control air so as to close the opening of the intake pipe 2b small. The capacity regulator 2a is controlled.

  Further, the calculation unit 50 calculates a required rotation speed of the engine 3 (see FIG. 1) based on the set pressure and notifies the engine rotation speed control unit 55 of the calculation. The engine rotational speed control unit 55 outputs an engine rotational speed control signal to the ECU 3a (see FIG. 1) via the engine rotational speed control signal output unit 54a, and determines the engine rotational speed of the engine 3 (see FIG. 1). The engine speed is controlled so as to be reduced.

  FIG. 4 is a front view showing an example of a mode of the discharge pressure setting unit. As shown in FIG. 4, the discharge pressure setting unit 52 includes an operation unit 52a for inputting a pressure value and setting the set pressure, and a display unit 52b for displaying the input pressure value. The The display unit 52b has a function of displaying the input pressure value as a numerical value of a required number of digits (for example, 4 digits) as a plurality of numerical values. The numerical value may be displayed by, for example, a 7-segment digital display. Although the aspect of the discharge pressure setting part 52 is not limited, the aspect in which the discharge pressure setting part 52 consists of the touchscreen T provided with the operation part 52a and the display part 52b can be considered. The operation unit 52a includes an up button U for increasing the pressure value displayed on the display unit 52b, a down button D for decreasing the pressure value, and a determination button E for determining the set pressure. The up button U can be operated in a direction to increase the numerical value displayed on the display unit by one, and the down button D can be operated in a direction to decrease the numerical value by one.

  In order to set the set pressure in the discharge pressure setting unit 52 having the form of FIG. 4, the up button U or the down button D is touched with a fingertip or the like, and the pressure value displayed on the display unit 52b is increased or decreased. Then, the set pressure can be set by an easy operation of displaying the desired set pressure value on the display unit 52b and touching the enter button E. If the touch on the up button U is continued, the displayed pressure value is fast-forwarded in the increasing direction, and if the touching the down button D is continued, the displayed pressure value is fast-forwarded in the decreasing direction. And a configuration that facilitates setting.

  Thus, by using the touch panel T for the discharge pressure setting unit 52, the discharge pressure setting operation and confirmation are facilitated, and an excellent effect of preventing erroneous operation can be obtained. Note that the mode of the discharge pressure setting unit 52 shown in FIG. 4 is an example, and for example, a mode in which the set pressure value is directly input by an operation button arranged in the form of a numeric keypad may be used. An aspect is not ask | required.

  The set pressure set by the discharge pressure setting unit 52 is preferably stored in the storage unit 51 (see FIG. 3) of the control unit 5, for example. When the set pressure is stored in the storage unit 51 in this way, when the engine-driven compressor 1 (see FIG. 1) is restarted, the calculation unit 50 (see FIG. 3) of the control unit 5 is stored in the storage unit 51. Since the set pressure stored in can be read and supplied as the discharge pressure, it can be set to the same discharge pressure as when the engine-driven compressor 1 is stopped.

  When the engine-driven compressor 1 having such a configuration is driven, an arbitrary discharge pressure can be supplied as follows (see FIGS. 1 to 4 as appropriate).

  FIG. 5 is a flowchart showing the flow of discharge pressure control by the calculation unit of the control unit. As shown in FIG. 5, when the engine-driven compressor 1 is started, the calculation unit 50 reads the set pressure stored in the storage unit 51 from the storage unit 51 (S1). And the calculating part 50 sets the engine speed of the engine 3 corresponding to setting pressure, and notifies the engine speed control part 55 (S2). The engine rotation speed control unit 55 notified of the engine rotation speed inputs an engine rotation speed control signal to the ECU 3a via the engine rotation speed control signal output unit 54a, and the requested rotation speed notified from the calculation unit 50; The rotational speed of the engine 3 input via the engine rotational speed input unit 53c is kept at an equivalent rotational speed.

  The engine rotation speed of the engine 3 corresponding to the set pressure may be stored in advance in the storage unit 51 as, for example, engine rotation speed setting data D1. Alternatively, a calculation formula for calculating the engine rotation speed from the set pressure may be incorporated in a program for driving the calculation unit 50. The calculation unit 50 reads the engine rotation speed setting data D1 from the storage unit 51, or calculates the engine rotation speed from the set pressure based on a calculation formula incorporated in the program, so that the engine rotation corresponding to the set pressure is calculated. Speed can be set.

  Next, the calculating part 50 sets the upper limit of the storage pressure set for every set pressure (S3). The upper limit value of the storage pressure is a pressure that is set as an allowable width with respect to the set pressure, and the storage pressure is a pressure that may be in a range from the set pressure to the upper limit value. Then, the correspondence between the set pressure and the upper limit value of the stored pressure may be stored in advance in the storage unit 51 as, for example, upper limit value data D2. Alternatively, a calculation formula for calculating the upper limit value from the set pressure may be incorporated in a program that drives the calculation unit 50. The calculation unit 50 can set the upper limit value of the storage pressure by reading the upper limit value data D2 from the storage unit 51 or by calculating the upper limit value from the set pressure based on a calculation formula incorporated in the program. .

  Next, the calculation unit 50 compares the storage pressure with the set pressure (S4), and when the storage pressure is equal to or lower than the set pressure (S4 → Yes), the electropneumatic proportional valve control signal output unit is added to the electropneumatic proportional valve 5a. The capacity regulator 2a is controlled so as to open the intake pipe 2b by outputting an electropneumatic proportional valve control signal via 54b (S5).

  When the storage pressure is larger than the set pressure (S4 → No), the calculation unit 50 controls the capacity regulator 2a based on the relationship between the upper limit value of the storage pressure for each set pressure and the storage pressure. The opening degree of the intake pipe 2b is adjusted (S6). The opening degree of the intake pipe 2b is adjusted by the capacity regulator 2a, and the capacity regulator 2a is controlled by the pressure of the control air output from the electropneumatic proportional valve 5a. An electropneumatic proportional valve control signal is input to the electropneumatic proportional valve 5a through 54b to adjust the pressure of the control air.

  The relationship between the opening of the intake pipe 2b and the pressure of the control air is determined by the characteristics of the capacity regulator 2a. The optimum relationship between the storage pressure and the opening of the intake pipe 2b may be set in advance as a design value for the entire engine-driven compressor 1. As described above, the relationship between the storage pressure and the control air pressure is set as the design value of the entire system of the engine-driven compressor 1 based on the characteristics of the capacity regulator 2a.

  FIG. 6 is a graph showing the relationship between the storage pressure and the control air pressure. The relationship shown in FIG. 6 is merely an example for explanation, and the optimum relationship may be determined based on the characteristics of each element constituting the engine-driven compressor 1. In FIG. 6, the vertical axis indicates the increase range with respect to the upper limit value of the storage pressure, and the horizontal axis indicates the increase range with respect to the upper limit value of the control air pressure. It is the figure which showed the relationship.

  The vertical axis in FIG. 6 shows the range of increase in the storage pressure from the set pressure as a percentage (%) with respect to the upper limit value of the storage pressure. When the storage pressure is 0, the storage pressure is equal to the set pressure. In the case of 100, the storage pressure is the upper limit value of the storage pressure. In addition, the horizontal axis in FIG. 6 indicates the increase in the pressure of the control air as a percentage (%) with respect to the upper limit value of the storage pressure, and when 0, the storage pressure is equal to the set pressure. The control air pressure is shown when the storage pressure is at the upper limit.

  FIG. 6 shows that it is preferable to increase the pressure of the control air as the storage pressure increases. As an example, point P1 in FIG. 6 indicates a point where the storage pressure has increased from the set pressure and has reached 80% of the upper limit value. At this time, since the increase width of the control air pressure indicates 60%, the control air pressure is preferably set to the same pressure as when the storage pressure is increased to 60% of the upper limit value. It is shown that.

  Data indicating the relationship between the storage pressure and the control air pressure as described above may be stored in the storage unit 51 in advance, for example, as control air pressure data D3. Alternatively, a calculation formula for calculating the pressure of the control air from the stored pressure may be incorporated in a program that drives the calculation unit 50. The calculation unit 50 reads out the control air pressure data D3 from the storage unit 51, or calculates the control air pressure from the storage pressure based on a calculation formula incorporated in the program, thereby corresponding to the storage pressure. The control air pressure can be set.

  Further, the pressure of the control air is detected by the second pressure sensor 5d, converted into, for example, an electric signal, and input to the calculation unit 50 via the second pressure signal input unit 53b. Therefore, the calculation unit 50 sets the electropneumatic proportional valve control signal output unit 54b so that the actual control air pressure detected by the second pressure sensor 5d is equal to the set control air pressure. Then, an electropneumatic proportional valve control signal may be input to the electropneumatic proportional valve 5a to control the opening degree of an open / close valve (not shown) of the electropneumatic proportional valve 5a.

  Next, the calculation unit 50 sets the engine rotation speed of the engine 3 corresponding to the stored pressure and notifies the engine rotation speed control unit 55 (S7).

  FIG. 7 is a graph showing the relationship between the storage pressure and the engine speed. Note that the relationship shown in FIG. 7 is merely an example for explanation, and an optimal relationship may be determined based on the characteristics of each element constituting the engine-driven compressor 1. FIG. 7 shows the relationship between the increase in the storage pressure and the decrease in the engine rotation speed, with the vertical axis indicating the increase range with respect to the upper limit value of the storage pressure and the horizontal axis indicating the decrease range with respect to the engine rotation speed during rated operation. FIG.

  The vertical axis in FIG. 7 indicates the range of increase in the storage pressure from the set pressure as a ratio (%) to the upper limit value of the storage pressure. When the storage pressure is 0, the storage pressure is equal to the set pressure. When the value is 100, the storage pressure is the upper limit value. In addition, the horizontal axis in FIG. 7 indicates the rate of reduction in engine rotation speed as a ratio (%) to the rated rotation speed. Here, the rated rotational speed is the engine rotational speed when the discharge amount of compressed air is maximum and the storage pressure is equal to the set pressure, and when it is 100, it indicates that the engine is operated at the rated rotational speed. When it is 0, it indicates that the engine is operating at no load and low speed idle rotation.

  FIG. 7 shows that it is preferable to reduce the engine speed as the storage pressure increases. As an example, point P2 in FIG. 7 indicates a point where the storage pressure has increased from the set pressure and has reached 80% of the upper limit value. At this time, the engine rotational speed indicates 10%, which indicates that the engine rotational speed is preferably operated at a point increased by 10% from the no-load low-speed idle rotation.

  Data indicating the relationship between the increase in the storage pressure and the engine rotation speed as described above may be stored in advance in the storage unit 51, for example, as the engine rotation speed reduction data D4. Alternatively, a calculation formula for calculating the engine rotation speed from the increase range of the storage pressure may be incorporated in a program for driving the calculation unit 50. The calculation unit 50 reads the engine rotation speed reduction data D4 from the storage unit 51, or calculates the engine rotation speed from the increase range of the storage pressure based on a calculation formula incorporated in the program, thereby increasing the increase range of the storage pressure. The engine speed corresponding to can be set. Then, the set engine speed may be notified to the engine speed control unit 55.

  Here, as shown in FIG. 3, the engine rotational speed of the engine 3 is detected by the rotational speed detecting means 3b and input to the engine rotational speed control unit 55 via the engine rotational speed input unit 53c. Therefore, the engine speed control unit 55 sends the engine speed to the ECU 3a via the engine speed control signal output unit 54a so that the engine speed notified from the calculation unit 50 is equal to the actual engine speed. A rotation speed control signal may be output.

  As described above, when the opening degree of the capacity regulator 2a and the engine speed of the engine 3 are controlled, when the stored pressure is equal to or lower than the set pressure, the intake pipe 2b is opened and the engine 3 is adapted to the set pressure. The stored pressure is increased by operating at the rotational speed, and the stored pressure is set to be equal to the set pressure.

  When the storage pressure exceeds the set pressure, the engine rotation speed of the engine 3 is reduced and the pressure of the control air is adjusted corresponding to the range of increase exceeding the set pressure. Then, when the storage pressure increases and reaches the upper limit (in FIG. 6 and FIG. 7, the increase in the storage pressure reaches 100%), the ratio of the control air pressure and the storage pressure is set in advance. The electropneumatic proportional valve is controlled so that the engine 3 operates at low idle speed (in FIG. 7, the engine speed is 0%). For this reason, the storage pressure does not rise above the upper limit value.

  When the set pressure is changed and a new set pressure is set by operating the operation unit 52a (see FIG. 3) of the discharge pressure setting unit 52 (S8 → Yes), the calculation unit 50 stores the data in the storage unit 51. The set pressure is updated (S9). Then, returning to S <b> 2, the calculation unit 50 sets the engine speed corresponding to the new set pressure, and notifies the engine speed control unit 55 of the engine speed. When the set pressure is not changed (S8 → No), the calculation unit 50 constantly monitors the stored pressure, and when a deviation from the set pressure occurs, as described above, the opening degree of the capacity regulator 2a. And the engine speed of the engine 3 is adjusted.

  As described above, the engine-driven compressor according to the present invention can easily change the set pressure by changing the set pressure by operating the discharge pressure setting unit 52, and can easily set the discharge pressure. There is an excellent effect.

  Moreover, since the engine drive compressor concerning this invention can set continuous arbitrary pressure as discharge pressure, there exists the outstanding effect that arbitrary discharge pressure can be supplied continuously from a low pressure to a high pressure.

  Furthermore, the control pressure is constantly monitored by the control unit 5 and the first pressure sensor 4c, and when the stored pressure fluctuates, feedback control can be performed so as to return to the predetermined stored pressure. Since the stored storage pressure is always stable, an excellent effect that a stable discharge pressure can be supplied is obtained.

It is a block diagram which shows schematic structure of an engine drive compressor. It is sectional drawing which shows the structure of a capacity | capacitance regulator. It is a block diagram which shows the structure of a control unit. It is a front view which shows an example of the aspect of a discharge pressure setting part. It is a flowchart which shows the flow of the discharge pressure control by the calculating part of a control unit. It is a graph which shows the relationship between storage pressure and the pressure of control air. It is a graph which shows the relationship between storage pressure and an engine speed.

Explanation of symbols

1 Engine Driven Compressor 2 Compressor Body 2a Capacity Regulator (Intake Control Valve)
2b Intake pipe 3 Engine 3a ECU
4 Oil chamber (storage means)
4c 1st pressure sensor (1st pressure detection means)
5 Control unit (control device)
50 arithmetic unit 51 storage unit 52 discharge pressure setting unit (pressure setting means)
52a Operation section 52b Display section 53 Signal input section 53a First pressure signal input section ( second electric signal input means)
53b Second pressure signal input section ( third electric signal input means)
53c Engine rotational speed input section ( first electric signal input means)
55 Engine Rotational Speed Control Unit 5a Electropneumatic proportional valve (valve control means)
5b Second pressure sensor (second pressure detecting means)
U Up button D Down button D1 Engine speed setting data

Claims (5)

An engine comprising a rotational speed detection means having a function of detecting a rotational speed, and a function of converting the detected rotational speed into a predetermined electrical signal and outputting the electrical signal ;
A compressor body driven by the engine;
Storing means for storing compressed air compressed by the compressor body;
First pressure detection means for detecting the pressure of the compressed air stored in the storage means;
Pressure setting means capable of setting an arbitrary discharge pressure;
An intake air control valve that adjusts an intake air amount of intake air that is sucked into the compressor body,
Control means for adjusting the intake air amount of the intake air to the compressor body by controlling the intake control valve so that the pressure in the storage means becomes equal to the discharge pressure ;
The control means includes
First electrical signal input means for inputting the electrical signal output by the rotational speed detection means;
A storage unit for storing engine speed setting data used to set the engine speed corresponding to the discharge pressure;
The engine speed calculated based on the electric signal input to the first electric signal input means is set based on the set discharge pressure and the engine speed setting data. An engine speed control unit that gives a command to the engine to be equal to
Engine-driven compressor according to claim Rukoto equipped with. The opening of the intake control valve is controlled by the pressure of control air input for opening adjustment,
Valve control means for controlling the opening of the intake control valve by outputting the pressure of the control air;
A second pressure detecting means for detecting the pressure of the control air; and the engine driven compressor further comprising:
The opening of the intake control valve is controlled by adjusting the pressure detected by the second pressure detection means via the valve control means so that the pressure in the storage means becomes equal to the discharge pressure. 2. The engine-driven compressor according to claim 1, further comprising control means for adjusting an intake amount of the intake air to the compressor body. The first pressure detection means and the second pressure detection means have a function of converting the detected pressure into a predetermined electric signal and outputting it,
The control means includes
Second electrical signal input means for inputting the electrical signal output by the first pressure detection means;
Third electrical signal input means for inputting the electrical signal output by the second pressure detection means;
Based on the electrical signal input to the second electrical signal input means, the pressure detected by the first pressure detection means is calculated, and based on the electrical signal input to the third electrical signal input means. A calculation unit for calculating a pressure detected by the second pressure detection unit;
The engine driven compressor according to claim 2, further comprising: The pressure setting means includes
A display unit for displaying the value of the discharge pressure with a plurality of numerical values;
An operation unit having an up button that can be operated in a direction to increase the numerical value displayed on the display unit by one; and a down button that can be operated in a direction to decrease the numerical value by one;
The engine drive compressor according to any one of claims 1 to 3, further comprising: The engine-driven compressor according to any one of claims 1 to 4 , wherein the valve control means is constituted by an electropneumatic proportional valve.

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